Active noise control for periodic disturbances

This paper proposes an active noise control algorithm for periodic disturba nces of unknown frequency, The algorithm is appropriate for the feedback ca se in which a single error microphone is used. A previously proposed algori thm for the rejection of sinusoidal noise sources is extended for the cance llation of multiple harmonics, Unlike many other approaches, the estimates of the frequencies of the separate harmonics are tied together within the a lgorithm to account for the integer multiplicative relations between them, The dynamic behavior of the closed-loop system is analyzed using an approxi mation that is shown, in simulations, to provide an accurate representation of the system's behavior. Experimental results on an active noise control testbed demonstrate the success of the method in a practical environment.